Researchers harness the fire of 70,000 suns using stacked solar cells

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Researchers at North Carolina State University have developed a simple fix to increase the efficiency of stacked solar cells dramatically. This new, more economical breed of solar panel could handle the energy concentration of 70,000 suns without losing voltage to waste heat.

Stacked solar cells are currently the most efficient type of cell on the market. They work by connecting several cells which are, as the name suggests, stacked on top of one another. These cells are capable of converting as much as 45% of light into energy. The problem comes when we try to concentrate the sun’s rays on solar cells.

Energy companies are working on perfecting lenses that can take the light from the sun, and focus it on solar cells at much higher intensity. This works well with stacked cells up to about 700 suns worth of light, but then the efficiency starts to drop off as the connection between cells leaches the voltage away as heat.

The breakthrough comes as a result of inserting a very thin film of gallium arsenide into the connection junction. This insulates the connections and prevents voltage from being lost. Early testing indicates the new connections could prevent a drop in efficiency at up to 70,000 suns of solar energy. That not likely to come up much in real life, though. The best lenses currently being developed concentrate the sun’s rays by about 4000-5000 times.

This easy fix means solar power companies can create a new generation of solar cells that can cope with highly concentrated sunlight. Instead of blanketing an area with solar panels, lenses can be used to send more light to a few high-efficiency panels.